Searching for the last substring after "\"

mulfycrowh

Hi,

Fo example, I have the directory "C:\examples\toys\vehicles\cars".
What would you suggest to use to get the substring "cars" ?
Any function in QDir or QString ?

Many thanks

Joel Bodenmann

Sounds like QDir::dirName is pretty much what you want.

the_

@mulfycrowh

There are several ways to do so.

One way could be to split the string with QString::split() which will return a QStringList. QStringList::last() will give you then the last element of this list, (you should check the size of the list if its >0)

mulfycrowh

Finally I use lastIndexOf on the QString to get the position of the last ""

Joel Bodenmann

@mulfycrowh said:

Finally I use lastIndexOf on the QString to get the position of the last ""

In case of you are dealing with file system paths I strongly recommend using QDir::dirName. It has been purposely-designed for that task.
Your method will already stop working if the system you're running on uses a different file path separator. You could use QDir::Separator() and still use your method of extracting but you might hit other problems down the track in the future.

Chris Kawa

QString has a specialized function exactly for this kind of task (works for any string and separator, not only paths): section():

QString path("C:\\examples\\toys\\vehicles\\cars");
QString last_part = path.section('\\', -1);

@the_ Please don't ever use split() for things like this. It creates a dynamically allocated linked list of dynamically allocated copies of parts of the string and then copies the last one. That's probably the slowest and most memory consuming way to do this.

mulfycrowh

Thanks. It runs perfectly

Joel Bodenmann

If you're not going to use QDir::dirName() please at least use QDir::Separator() in your QString::section() function. Do yourself a favor :)
Otherwise it won't work on any system that uses a separator other than \ (which is almost every system except Windows).

mulfycrowh

I mean with dirName